One of the biggest workflow mistakes people make is fielding messages on a rolling basis. They drop whatever they're doing to check a notification, even if they have no plans to respond immediately. To Christian, this is horribly inefficient.

"Humans and computers alike pay a penalty for starting a new task or interrupting the task that they're on," he tells Tech Insider. That penalty is reduced output, or productivity.

"At the extreme, you can find yourself in a situation where you are so frantically switching your attention between so many different things," Christian explains, "that you fail to make any progress on any of them. In computer terms, this is called thrashing. If you've encountered the giant spinning beach ball of doom, you have perhaps seen thrashing firsthand in your machine."

The remedy for thrashing: Just slow down.

"In these cases, there's clearly no way to work harder," the authors write in the book, "but you can work ... dumber."

In other words, minimize how often you switch contexts or tasks, and you'll increase how much time you can actually spend working. According to Christian, the simplest way to do that is by "batch-processing" your tasks: commit to work for an entire hour without looking at email, and only check your messages on a set basis, like every hour or every odd hour.

But you must also be strategic when you do check and reply to those emails, Christian warns, because his strategy will likely cause more messages to pile up than you're used to. Here, too, simplicity is king.

To avoid thrashing while checking emails, minimize the time you spend thinking about or answering them. Don't waste time deciding which emails need a response first, since that's a surefire way to spend more time designing your workflow than actually working, Christian says.

Instead, check one email at random — say, the one at the top — evaluate if it needs a response, and respond if it does. If it doesn't, move on. Whatever small amount of time you'd save by responding to the "highest-priority" emails first would likely be used up by sorting through your inbox in the first place.

So batch-process your email and respond at random. Future you — productive you — will be happy that you did.